RegionalGEM15 km

OPERATIONAL 48-h RUN (00 or 12 UTC)

EVENT

GEM-LAM2.5 km

GEM-LAM1 km

MC2-LAM250 m

T+5

T+12

T-1

T-3

36-h run

15-h run

6-h run

MicroscaleUrban flow

Models (urbanSTREAM)

IC + LBC

IC + LBC

IC + LBC

IC + LBCGlobalVariable resolution576 x 641Timestep = 7.5 min58 levels (for NWP)1D turbulence No TEB

LAM201 x 201Timestep = 60 s53 levels (two levels of packing near surface)1D turbulence TEB

LAM201 x 201Timestep = 30 s53 levels (two levels of packing near surface)1D turbulence TEB

LAM201 x 401 (long axis oriented along the low-level wind direction)Timestep = 10 s53 levels (two levels of packing near surface)3D turbulence TEB

From Mesoscale to MicroscaleFrom Mesoscale to Microscale

12 UTC 00 UTC 12 UTC

13 UTC

1. Coupling variables

2. Surface layer coupling

3. Lateral boundary conditions

4. 250-m vs 1-km results

Coupling Between Mesoscale and Microscale

GEM-LAM1 km

MC2-LAM250 m

T+5

T+12

T-1

T-3

15-h run

6-h run

MicroscaleUrban flow

Models (urbanSTREAM)

IC + LBC

IC + LBC

Inflow boundary conditions

•Horizontal wind

•Vertical motion

•Turbulent Kinetic Energy

•Boundary-layer height

Atmospheric model

zatm

Vegetated canopyUrban canopy

Flat surfaces

The Surface in GEM The Concept

FLUX AGGREGATION

SURFACE = TOP of CANOPY

First atmospheric level, about 50 m above the surface

Surface layer

zatm+zblg

zatm+(zblg-zveg)zatm

Vegetated canopy Urban canopyFlat surfaces

GEM’s Surface: How it connects with the Real World

Atmospheric model

First atmospheric level, about 50 m above the surface

Logarithmic wind profiles over each type of surfaces

1ln)( *

oz

z

k

uzV

W

zzzzVzV bldbld 2

exp)()(

GEM’s Vertical Wind Profiles vs Observations at Station ANL (IOP9)

RADAR

SODAR

GEM

GEM’s Vertical Wind Profiles vs Observations at Station ANL (IOP9)

RADAR

SODAR

GEM

NATURAL

CANYON

IOP9 (Night): Daytime turbulence IOP9 (Night): Daytime turbulence

26 July 2003 20 UTC 26 July 2003 21 UTC

More turbulent

Less turbulent

One hour later, the turbulence is more homogeneous

Automation and TestingAutomation and Testing

We propose to run the prototype in a fully automatic manner at a regular frequency (once a week or once a month?).

• Specify location of event (lat, lon)

• Generation of computational grids (250-m grid is oriented along the mean daytime low-level winds)

• Production of surface fields using an interpolation from pre-processed large grids (for Montreal, Toronto, Ottawa, and Vancouver)

• Integration of 2.5-km, 1-km, and 250-m runs

• Production of outputs for microscale models (with adaptation to local surface characteristics)

FULLY AUTOMATIC PROCESS

Computational CostComputational Cost

200 x 200 x 53 x 2160 (36h) 35 min with 200 cpus2.5 km

200 x 200 x 53 x 1800 (15h) 30 min with 200 cpus1 km

200 x 400 x 53 x 2160 (6h) 65 min with 400 cpus250 m

Total of 110 min

ni x nj x nk x nsteps Wall clock timeGrid size

On CMC’s current operational machine…

On new computer (early 2007), 2.5 times faster, i.e., 45 min.

CRTI-1 Further WorkCRTI-1 Further Work1. Urban cover classification

– finalize vector data (MTL and VAN)– examine hybrid approach? (satellite + vector)– other cities (TOR, Ottawa,?)– Pre-processing of large grids for selected cities (MTL, VAN, OTT, TOR)

2. Urban anthropogenic fluxes– generation for MTL (+ validation with Quebec Region data)– modify GEM inputs to include anthropogenic fluxes– sensitivity study on OKC: impact on mixing in boundary layer

3. Prototype – complete OKC and apply to MTL (with MUSE)– output adaptation for microscale modeling (coupling issue)– current prototype with MC2-250m (waiting for updated GEM vertical discretization)– start running prototype (e.g. once a week?)

4. 3D turbulence – finalize code validation with LES-type runs– impact study with 250-m runs

5. MUSE – continue analyses of MUSE-1 and MUSE-2 data

6. TEB – cascading of TEB prognostic variables (for initialization purpose)– snow treatment

7. Publications…